Have a Perfect Powder Measure from around 2001. Like most PPM's, it leaked ball & flake powders badly. Lapped the drum into the seat with valve grinding coupound, finished with Turtle Wax Chrome Polish.
It's a completely different device. Smooth, leaks even Titegroup -the finest powder I've used - only a tiny bit, most not at all. Runs smoothly as I don't have to tighten the Bejeezus out of it. Measures within .1 gr when I'm consistent.
Many users seem to find the Auto Drum fine but a few report the same results as you. It could be tolerance stacking in the unfavorable direction resulting in a lousy fit between drum and seat.
My two cents is that unless we could all afford only the most expensive hardware, we'll encounter this - even then, I've seen reloaders occasionally report issues with Forster, Whidden and Redding products.
Lee makes inexpensive products that mostly do their job and are sometimes an outstanding value. Part of their low price is material choice, like the molded plastic drum in drum measures, part is (lack of) in-depth QA.
I'd bet a six-pack of great beer that measuring a hundred Auto Disk drums would result in 'generous' variations from the design standard, perhaps caused by post-mold shrinkage. You could send the drum or the entire measure back to Lee; if eight or nine out of ten work as intended the odds are in your favor.
But you handload for more than just economy, correct? You build ammo tailored to your needs - at a lower cost than buying an off-the-shelf equivalent, if there even is one. I don't hesitate to tweak my stuff - within reason - to make it meet my expectations.
I'd examine the measure carefully, especially the machined seat and if all looks well, try lapping in the drum. It'll wear in faster than the seat, even though the measure body is a zinc alloy, so the measure's unlikely to end up FUBAR'd.
If you elect to do so, please report on your results. It's a data point either way.
TL;DR: Try lapping the drum and let the sub know your results.